Wind wheel and electricity generator using same

ABSTRACT

A wind-driven power source comprises a propeller-driven rotor structure and a stator structure carrying clusters of copper-wire wound ferromagnetic cores as voltage generators. The cores are arranged in pairs spaced apart by hard rubber rollers which engage the inside surface of a load ring forming part of the rotor structure. The overall rotor structure comprises the large diameter load ring, a smaller diameter root ring and a plurality of aerodynamic blades extending radially outwardly from the root ring and secured either by saddle blocks or integral bonding to the load ring. The load ring may be aluminum or plastic. Permanent magnets are arranged around the load ring to interact with the voltage generator structures to produce three-phase electricity.

RELATED APPLICATION

This application is a divisional of U.S. application Ser. No. 10/995,729filed under attorney docket no. RHB-100-A on Jul. 26, 2005, currentlypending. The content of the U.S. patent Ser. No. 11/190,026 isincorporated herein by reference.

FIELD OF THE INVENTION

This patent relates to wind wheels and to wind-driven electricitygenerators using wind wheels. More particularly, the disclosure hereindescribes a wind-driven generator of minimal complexity, lightweight andoptimized efficiency which can be constructed of low cost components.

BACKGROUND

It is known to use wind wheels to perform mechanical functions and togenerate electricity. An early wind wheel electrical generator isdisclosed in U.S. Pat. No. 1,233,232, issued Jul. 10, 1917, to A. H.Heyroth. The Heyroth wind wheel comprises a large diameter rotor ringcarrying permanent magnets and a center axle which supports the rotorring by means of radial spokes. Rotation of the rotor ring causes thepermanent magnets mounted thereon to move past stationary magnetic coresand the changes of flux value through the cores result in the generationof electrical voltages in windings carried by the cores.

A similar but more recent device is shown in U.S. Pat. No. 6,064,123,issued May 16, 2000, to Nils Gislason.

Still another device is shown in U.S. Pat. No. 6,664,655 issued Dec. 16,2003, to Charles S. Vann. The Vann wheel comprises a large number ofshort radial blades fixed between two large-diameter, concentric metalrings. The outer ring is supported for rotation on three outside rollersand the ring can be magnetized so as to form part of a voltage generatoror a motor.

SUMMARY

This disclosure describes a wind wheel particularly, but notexclusively, suited for use in an electricity generator. To the extentso used, the generator involves optimal application of the followingprinciples:

-   1. Higher rotor speeds generally result in higher generator output    power.-   2. Higher rotor speeds are more easily achieved with a lighter,    lower-mass rotor structure; and-   3. It is advantageous to minimize torque and moments drag forces on    the rotor structure.

The wind wheel of the present invention affords optimal use of theseprinciples in a rotor structure comprising shell diameter root ring, alarger diameter outer ring, and a plurality of lightweight bladesstructurally connected at their inner ends to the root ring and at amidpoint to the outer ring. The outer ring is used in a rotary supportsystem typically using rollers to allow the rotor to rotate about anaxis which is common to the root and outer rings.

When used in an electricity generator, the lightweight rotor can carry aplurality of spaced permanent magnets to co-act with one or morestationary core arrangements to produce electricity as the rotorrotates.

The present arrangement requires no center axle and has the potential toproduce high rotor speed for any given wind force or speed without theneed for a gear box. The use of a midpoint structural ring providingsupport at the midpoints of the blade allows for the use of lightweightmaterials such as foam core composition for blade construction.

These and other advantages of the invention will be best understood froma reading of the following specification which describes the preferredembodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The description herein makes reference to the accompanying drawingswherein like reference numerals refer to like parts throughout theseveral views, and wherein:

FIG. 1 is a perspective view of a portion of a “wind farm” employingthree generators constructed in accordance with the present inventionand mounted on poles;

FIG. 2 is a detail of one of the generators of FIG. 1;

FIG. 3 is a cross-section of one of the propeller blades of thestructure of FIG. 2;

FIG. 4 is a detail of the structure of FIG. 2 showing the arrangement ofvoltage generator core structures straddling an inside roller as part ofthe stator structure for the device of FIG. 2;

FIG. 5 is a detail of the structure of FIG. 2 showing the corestructures, permanent magnets and propeller blade mounting structure inthree-dimensional detail;

FIG. 6 is a side view of the structure of FIG. 5 showing part of therotor in cross-section;

FIG. 7 is a cross-section of a blade showing additional rotor structure;

FIG. 8 is a representative circuit diagram generating three-phased powerfrom the structure of FIGS. 1-7;

FIG. 9 is a plan view of an alternative embodiment of a rotor structure;and

FIG. 10 is a partial cross-section of the structure of FIG. 9 in greaterdetail showing the support rollers for the rotor of FIG. 9 and therelationship between the permanent magnets and the voltage-generatingstructures mounted on the stator.

DETAILED DESCRIPTION

Referring first to FIG. 1, there is as shown a portion of a “wind farm,”including identical wind-driven power sources 10, 11 and 12 mounted onpoles 14, 15 and 16 to collect wind and produce electricity from theenergy contained therein. Since all of the sources 10, 11 and 12 areidentical, only source 10 will be described in detail.

Referring now to FIGS. 2-7, source 10 comprises a stator structure 18made up of three triangularly arranged aluminum struts 19 mounted on thepole 14. The stator structure 18 includes three generating units 20 and21 mounted on plates 50 and 22 described in greater detail withreference to FIGS. 4 and 5. Again, the units 20, 21 and 22, although indifferent locations on the power source 10, are identical and unit 20 isdescribed as representative.

Unit 20 comprises two ferromagnetic iron cores 26 and 28 closelyarranged around opposite sides of and straddling a roller 30 which isone of three stator-mounted rollers symmetrically arranged on the plate50 of the stator structure 18. The rollers 30 support a rotor structure32, the largest component of which is an aluminum ring 34. This isvariously referred to herein as the “outer ring” or the “load ring” and,in this embodiment, includes a number of components, including a ferrousmetal backer ring 48 and an array of permanent magnets 36 bonded to theradially inner surface of the broken ring, to generate electricity. Thealuminum ring 34 makes the structure light and easy to accelerate whilethe iron backer ring 48 provides a flux path for the magnetic system.The rotor structure 32 further includes lightweight compositeaerodynamic blades 38, 40 and 42 which, as best shown in FIGS. 2 and 3,are preferably made by overlaying a rigid foam plastic core 44 with asynthetic resin exterior covering 46.

The rotor structure 32 further comprises a non-ferrous root ring 45 towhich the blades 38, 40 and 42 are attached at their inner ends. Theroot ring 45 may be of a composite, plastic construction or of otherrelative lightweight material. By way of example, the blades 38, 40 and42 may be approximately five feet in length. The root ring 45 may beapproximately two feet in diameter and the aluminum load ring 34 may beapproximately six feet in diameter. As such, the load ring 34 isattached near the radial midpoint of the rotor structure 32 to addstrength and rigidity to the blades to resist torque deflection. Theblades are cambered with the pitch of approximately forty-two degrees atthe inner or root end thereof and approximately one-half of one degreeat the outside tips. The pitch changes gradually from end to end.

Referring to FIGS. 2 through 5, the stator and rotor structures will bedescribed in greater detail. The stator structure 18 comprises aluminumplates 50 at the apices of the triangular support struts shown in FIG.6. Each plate 50 holds a pair of spaced apart, laminated, iron cores 26and 28 wound with copper coils 29 and 31. Between each set of two corestructures 26 and 28 is rotatably mounted a hard rubber roller 30 whichengages the outer surfaces of a polycarbonate track 52 running over theoutside surfaces of the permanent magnets 36 which are bonded to a steelbacker ring 48 mounted on the aluminum load ring 34 to provide acontinuous magnetic flux path. Non-magnetic spacers 33 are disposedbetween the permanent magnets 36. The polycarbonate track 52 is a thinfilm bonded over the flat surface defined by the combination of themagnets 36 and the spacers 33, as best shown in FIGS. 5 and 6.

The rollers 30 make contact with and ride on the flat surface providedby the polycarbonate track 52 for smooth vibration-free rotation of theload ring 34 of the rotor structure 32. The ferromagnetic cores 26 and28 are located in close proximity to but spaced from the polycarbonatering by approximately 0.180 inch. In a practical embodiment of the sizedescribed above, it has been found that the magnetic force of attractionbetween the permanent magnets and the ferromagnetic core structures 26and 28 is approximately 40 pounds per voltage generation unit for atotal of 80 pounds of attraction at each of the three stator structures18 as the magnetic rotor rotates past. In order that the aluminum loadring 34 be able to withstand these attractive forces without deflection,the rotor rollers 30 are preferably mounted symmetrically between theclosely matched pairs of cores 26 and 28 for maximum resistance todeflection so that they contact the inside surface of the load ringdirectly between the core structures. Additional rollers 37 arerotatably mounted behind the stator structure as shown in FIG. 6 toprovide thrust support; i.e., support in the direction parallel to theaxis of rotation.

The blade support structure is best shown in FIGS. 5, 6 and 7 tocomprise saddle blocks 54 which receive and conform to the insidesurfaces of each of the blades 38, 40 and 42. Clamp blocks 56 and 58attach by way of cap screws to the saddle blocks to trap the blades 38,40 and 42 and hold them firmly to the load ring 34 for overall rigidity.

Stops 58 are preferably attached by cap screws to plates 60 on thestators 18 to prevent the rotor 32 from moving forwardly of the statorstructure. The spacing between the stops 59 and the outer surface of theload ring 34 may be on the order of ¼ inch; minimal reverse thrustloading is experienced and thus no outside rollers are required.

By way of summary, each of the generator units comprises a statorstructure 18 consisting of a triangular frame made of struts 19 andthree symmetrically arranged pairs of generating units 20, 21 and 22.Each generating unit includes a pair of ferromagnetic cores 26 and 28and wound coils straddling a roller 30 adapted to ride on the radiallyinner track 52 of the load ring 34. The load ring 34 is integrallyattached to each of the lightweight propeller blades 38, 40 and 42 atapproximately the midpoints thereof to add structural stiffness. Theinside surface of the load ring 34 is provided with an array ofpermanent magnets 36 which move in radially spaced relationship to thestator cores 26 and 28 to generate voltages in the cells as thepropeller blades 38, 40 and 42 drive the rotor ring in a circular path.

Referring now to FIG. 8, a representative electrical system based on theuse of 160 permanent magnets on the inside of the six foot load ring 34is shown. The system comprises clusters 64, 66 and 68 of six coils eachspaced to create a three-phase electrical system. The two matching-phasecoils in each cluster are wired in series. There are six identicalclusters. Each cluster has its respective matching phased coil pairswired in parallel to form an output circuit. Each of these outputcircuits has a capacitor bank 70, 72 and 74 connected between the leadsto correct the power factor. Each circuit is then fed to one of thefull-wave rectifiers 76, 78 and 80, respectively, to provide unregulatedDC voltage to an output circuit comprising resistors 84, 86 and 88. Thecircuit of FIG. 8 shows voltage meters in strategic locations to monitoroutput. Each coil is in a representative example consisting of 100 turnsand the air gap between the cores of the generator structures and themagnets are approximately five millimeters.

In a successfully operated embodiment, the weight of the blades areapproximately 36 pounds total and safely rotated at a speed of up to 250revolutions per minute. The total weight of the magnets is approximately15 pounds and the rollers 30 are 4 inches in diameter and made of hardrubber.

Referring now to FIGS. 9 and 10, an alternative rotor structure 100 willbe described. The rotor structure comprises a load ring 102 made ofmolded lightweight plastic and having an aerodynamic or wedge-shapedcross-section as shown in FIG. 10. The plastic load ring 102 isphysically integrated with the blades 104, 106 and 108 at approximatemidpoints thereof as shown in FIG. 9. The inner ends of the blades arebonded by standard fiberglassing techniques to the smaller diameter rootring 110. The term “fiberglassing” is intended to encompass compositestructures of various kinds including those using fibers of graphite,glass and other materials.

Whereas the permanent magnets 36 of the embodiment of FIG. 4 are mountedon the radially inside surface of the load ring 34, the permanentmagnets 114 of the embodiment of FIGS. 9 and 10 are arrayed annularlyaround the leeward or downwind surface 130 of the load ring 102 and arebonded to an annular ferromagnetic backer ring 112 which is cast intothe load ring 102 as shown in FIG. 10. A plastic surface can be placedatop the magnets for weather proofing. Rollers 124 bear against theinside surface 126 of the load ring 102 and are arranged in thesymmetrical and equally-spaced arrangement shown in FIG. 9. Thoserollers are carried by the stator structure 116 which, like the firstembodiment, is made up of a triangular arrangement of beams.Ferromagnetic core structures 118 with wound coils 120 are also placedon the stator structure 116 closely adjacent to the track of thepermanent magnets 114 as the rotor rotates. Thrust support is providedby means of rollers 128 which bear against the surface 130 radiallyinboard of the track of the permanent magnets 114.

In this embodiment, the generating units are essentially out of theairstream, i.e., in the shadow of the load ring 102 to reduce losses dueto windage. Only the radial rollers 124 and smaller portions of thestator structure lie in the windstream. This structure may be madeextremely light in weight and extremely rigid because of the possibilityfor integrating with epoxy-bonding, fiberglassing techniques and thelike. The electrical arrangement of FIG. 8 may also be used incombination with the structures of FIGS. 9 and 10.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiments but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims, which scope is to be accorded the broadestinterpretation so as to encompass all such modifications and equivalentstructures as is permitted under the law.

1. A wind wheel comprising: a root ring having an axis of symmetry; anouter ring concentric with said root ring; a plurality of aerodynamicblades pitched to be rotated by wind moving parallel to said axis ofsymmetry; each of said blades being secured at its inner ends to saidroot ring and at a midpoint to said outer ring; and means for rotatablysupporting said wheel by way of said outer ring.
 2. A rotor as definedin claim 1, further comprising a plurality of magnets attached to asurface of said outer ring.
 3. A rotor as defined in claim 2, whereinsaid surface is a circumferential leeward surface.
 4. A rotor as definedin claim 1, wherein said outer ring is made of aluminum.
 5. A rotor asdefined in claim 1, wherein said outer ring is made of plastic.
 6. Astator structure for a wind-driven generator having a permanent magnetrotor comprising: a pair of ferromagnetic core structures with coilsmounted therein; and a roller disposed immediately between said corestructures for engagement with the surface of said rotor.